光电催化材料表界面电荷转移成像研究

Charge separation is one of the central themes of photocatalysis. However, heterogeneous photocatalyst are one of the most extreme complex systems because of the structure relationship with sequential light absorption, charge separation and surface photocatalytic reaction. With the development of first UV Raman spectrograph in China and spatially resolved surface photovoltage spectroscopy, the applicant and the research group had made many breakthroughs in the characterization of catalytic materials and were awarded the send prize of national nature science award. With the advantage of these home-made tools, the understanding of the hetero/homo phase junctions, facet charge separation and dual cocatalysts on the surface of semiconductor can greatly increase the photogenerated charge separation efficiency. With the visualization of the built-in electric field and vectorial charge separation, this project will try to gain deep insight into the driving force of the charge separation at the surface and interface of semiconductor photocatalyst. The obtained knowledge will provide basis for the rational design of high efficient photocatalysts.

光催化分解水及耦合CO2还原是世界性科学难题，发展在微纳米层次上研究光电、光化学转化机理的新方法，才能从根本上解决这一世界性难题。项目申请人及其所在研究团队在催化表征仪器研制方面有很好的研究积累，研制的我国第一台用于催化材料研究的紫外激光拉曼光谱（国家自然科学二等奖）和光催化粒子的空间分辨表面光电压谱有效的推动了半导体表面异质结、异相结，晶面电荷分离以及双助催化剂大幅增强光催化活性的等新概念的提出。本项目拟基于前期基础，创新性的利用纳米电极产生的局域电场与光吸收耦合，发展超分辨光生电荷吸收光谱成像以及表面光电压成像，同时具备毫微秒时间尺度的载流子动力学研究能力。该仪器将用于研究光电催化材料微纳米结构表/界面结构电荷分离驱动力，实际反应过程中电荷传输动力学以及空间特性，发展微纳尺度光电催化材料光生电荷分离和催化反应的新原理和新概念，从根本上推动在微纳米层次上设计和构筑高效光催化体系。

近年来针对太阳能光催化中光生电荷空间分离机制的科学前沿问题，在国际上率先发展高空间分辨表面光电压成像新方法，依托此方法在微纳尺度直接观测到光催化材料微纳尺度电场分布对电荷分离的主导性贡献，提出利用对称性破缺（光照、铁电和缺陷等）实现内建电场定向构筑，增强光生电荷分离的策略和理论，进一步，基于上述理解在纳米层次通过对局域电场调控，实现高浓度光生电荷向催化反应活性位的精准输运，极大提升水氧化效率。以通讯作者在Nat. Energy, National Sci. Rev., Angew Chem., Adv. Mater., Nano Letters，J. Phys. Chem. Lett., Chem. Soc. Rev.,等国际权威期刊发表论文7篇。受邀在英国法拉第论坛、美国高登会议做主旨报告。所发展的方法已经在国内外多家知名实验室的研究工作中得到应用。